Who killed Sister Cathy? A question that has plagued the city of Baltimore for almost 50 years.

Now, viewers are set to be haunted by that same 1969 murder, with the unsolved case the basis for Netflix’s next addictive true crime show.

The trailer for the new series, titled The Keepers, was unveiled on Thursday, seemingly showing a mix of Making a Murderer and the film Spotlight.

The seven-part documentary tells the story of Sister Catherine "Cathy" Cesnik, an English teacher at Archbishop Keough High School, who was murdered in November 1969 at the age of just 26.

According to the Daily Mail, two months after Sister Catherine was last seen buying a gift for her cousin, her body was discovered by hunters when they stumbled across her car only a block away from her apartment.

Despite speculation over the years, no one has ever been charged for the young nun's death.

The documentary brings together her former students and friends who launched their own investigation into the nun’s murder last year.

The rogue investigation was motivated by rampant suspicion that it was committed by priests to cover up a deep history of abuse and corruption.

"Baltimore’s always been a quintessentially Catholic city. The priests were the authority. Whatever they told you to do, you did," the first voice of the trailer says.

"The city has its level of corruption," the next voice adds.

As the detailed in the trailer, decades after Sister Catherine’s death people came forward about the alleged sexual abuse that occurred at the Catholic high school.

"I can testify that over 100 victims have been abused," one whistle-blower says.

Finally alluding to a cover up, the trailer ends with a chilling anecdote: "This goes bigger and deeper than we can imagine."

The seven-part series created by Tripod Media and Film 45 will launch on Netflix on May 19.